Tire

Abstract

To provide a tire capable of exhibiting superior traction performance and braking performance while maintaining a lateral grip.SOLUTION: The present invention relates to a tire which has a tread part 2. A plurality of circumferential grooves 3 provided at the tread part 2 are arranged all mutually in zigzag phase. A first crown land part 11 is sectioned by a plurality of first inclined grooves 16 into a plurality of first crown blocks 18. A second crown land part 12 is sectioned by a plurality of second inclined grooves 17 into a plurality of second crown blocks 19. A plurality of first shoulder lateral grooves 21 provided at first shoulder land parts 8 link first tread ends T1 to first shoulder circumferential grooves 5, and also extend along the tire axis. A plurality of second shoulder lateral grooves 22 provided at second shoulder land parts 9 link second tread ends T2 to second shoulder circumferential grooves 6 and also extend along the tire axis.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a tire. [Background technology]

[0002] Patent Document 1 below proposes a tire for rough terrain use suitable for dirt trials and the like. This tire includes at least three main grooves that extend continuously in a zigzag pattern. These main grooves are also arranged with the zigzag phase aligned. The tire of Patent Document 1 exhibits excellent lateral grip due to the main grooves, improving vehicle controllability. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Publication No. 2020-147162 Summary of the Invention [Problem to be solved by the invention]

[0004] Although the above-mentioned tires exhibit excellent lateral grip, they tend to lack grip in the tire circumferential direction, and there is room for improvement in traction performance and braking performance.

[0005] The present invention has been devised in view of the above circumstances, and has as its main object to provide a tire that can exhibit excellent traction performance and braking performance while maintaining lateral grip. [Means for solving the problem]

[0006] The present invention provides a tire having a tread portion, the tread portion including a first tread edge, a second tread edge, a plurality of circumferential grooves extending continuously in a zigzag pattern in the tire circumferential direction between the first tread edge and the second tread edge, and a plurality of land portions separated by the circumferential grooves, the plurality of circumferential grooves including a first shoulder circumferential groove adjacent to the first tread edge, a second shoulder circumferential groove adjacent to the second tread edge, and at least one crown circumferential groove disposed between the first shoulder circumferential groove and the second shoulder circumferential groove, all of the plurality of circumferential grooves being arranged with their zigzag phases aligned with one another, the land portions including a first shoulder land portion including the first tread edge, a second shoulder land portion including the second tread edge, a first crown land portion adjacent to the first shoulder land portion, and a second crown land portion adjacent to the first crown land portion, the first crown land portion is divided into a plurality of first crown blocks by a plurality of first inclined grooves inclined in a first direction with respect to the tire axial direction; the second crown land portion is divided into a plurality of second crown blocks by a plurality of second inclined grooves inclined in a second direction with respect to the tire axial direction, the second crown land portion being divided into a plurality of second crown blocks by a plurality of second inclined grooves inclined in a second direction opposite to the first direction with respect to the tire axial direction; the first shoulder land portion is divided into a plurality of first shoulder blocks by a plurality of first shoulder lateral grooves, the plurality of first shoulder lateral grooves connecting the first tread edge and the first shoulder circumferential groove and extending along the tire axial direction; the second shoulder land portion is divided into a plurality of second shoulder blocks by a plurality of second shoulder lateral grooves, the plurality of second shoulder lateral grooves connecting the second tread edge and the second shoulder circumferential groove and extending along the tire axial direction. [Effects of the Invention]

[0007] By adopting the above-described configuration, the tire of the present invention can exhibit excellent traction performance and braking performance while maintaining lateral grip. [Brief explanation of the drawings]

[0008] [Figure 1] 1 is a development view of a tread portion of a tire according to one embodiment of the present invention. [Figure 2] FIG. 2 is an enlarged view of a first crown land portion and a second crown land portion of FIG. [Figure 3] FIG. 2 is an enlarged view of the first shoulder land portion and the second shoulder land portion of FIG. [Figure 4] FIG. 4 is a development view of a tread portion according to another embodiment of the present invention. [Figure 5] FIG. 2 is a development view of a tread portion of a tire of a comparative example. DETAILED DESCRIPTION OF THE INVENTION

[0009] An embodiment of the present invention will be described below with reference to the drawings. The drawings are intended to illustrate the features of the present invention, but may include exaggerated representations and representations that differ from the dimensional ratios of the actual structure to facilitate understanding of the present invention. Furthermore, identical or common elements are designated by the same reference numerals throughout the embodiments, and redundant explanations will be omitted. Furthermore, well-known configurations may be appropriately adopted for configurations not described in this specification.

[0010] 1 is a development view of a tread portion 2 of a tire 1 showing one embodiment of the present invention. The tire 1 of this embodiment is suitably used as a tire for traveling on rough terrain at high speeds, such as in dirt trials and rallies. However, the present invention is not limited to such an embodiment.

[0011] 1, the tread portion 2 includes a first tread edge T1 and a second tread edge T2. The first tread edge T1 and the second tread edge T2 each correspond to the edge of the contact patch when the tire 1 in a normal state is loaded with 100% of the normal load (i.e., the maximum load specified for each tire in each of the standards below) and the tread portion 2 is brought into contact with a flat surface at a camber angle of 0°.

[0012] "Normal condition" means, in the case of a pneumatic tire for which various standards are established, a state in which the tire is mounted on a normal rim, inflated to the normal internal pressure, and no load is applied. In the case of a tire for which various standards are not established, the normal condition means a standard use state according to the intended use of the tire, in which the tire is not mounted on a vehicle and no load is applied. In this specification, unless otherwise specified, the dimensions of each part of the tire are values ​​measured in the normal condition.

[0013] A "genuine rim" is a rim that is defined for each tire by the standard system that includes the standard on which the tire is based. For example, in the case of JATMA, it is called a "standard rim," in the case of TRA, it is called a "design rim," and in the case of ETRTO, it is called a "measuring rim."

[0014] "Normal internal pressure" is the air pressure specified for each tire by each standard in the standard system, including the standard on which the tire is based. For JATMA, it is the "maximum air pressure," for TRA, it is the maximum value listed in the table "TIRE LOAD LIMITS AT VARIOUS COLD INFLATION PRESSURES," and for ETRTO, it is the "INFLATION PRESSURE."

[0015] For pneumatic tires for which various standards are established, "normal load" refers to the load specified for each tire in the standard system including the standard on which the tire is based. For JATMA, this is "maximum load capacity," for TRA, this is the maximum value listed in the table "TIRE LOAD LIMITS AT VARIOUS COLD INFLATION PRESSURES," and for ETRTO, this is "LOAD CAPACITY." For tires for which various standards are not established, "normal load" refers to the maximum load that can be applied when using the tire in accordance with the above standards.

[0016] The tread portion 2 of this embodiment has a specified orientation for installation on a vehicle. As a result, the first tread edge T1 is intended to be located on the inside of the vehicle when installed on the vehicle. The second tread edge T2 is intended to be located on the outside of the vehicle when installed on the vehicle. The orientation for installation on the vehicle is indicated, for example, by letters or symbols on the sidewall portion (not shown).

[0017] The tread portion 2 includes a plurality of circumferential grooves 3 extending continuously in a zigzag pattern in the tire circumferential direction between a first tread edge T1 and a second tread edge T2, and a plurality of land portions 4 therebetween.

[0018] The circumferential groove 3 alternately includes first inclined portions 3a inclined in a first direction (upward and to the right in each drawing of this specification) with respect to the tire axial direction and second inclined portions 3b inclined in a second direction (downward and to the right in each drawing of this specification) that is opposite to the first direction with respect to the tire axial direction. As a result, the circumferential groove 3 alternately includes first peaks 3c that are convex toward the first tread edge T1 side and second peaks 3d that are convex toward the second tread edge T2 side in the tire circumferential direction. The first inclined portions 3a and the second inclined portions 3b are each inclined at an angle θa of 45 to 55° with respect to the tire circumferential direction. As a result, the angle between the first inclined portions 3a and the second inclined portions 3b is an acute angle. In this embodiment, for each circumferential groove 3, the inclined portions are arranged within the above-mentioned angle range.

[0019] The groove width W1 of the first inclined portion 3a and the second inclined portion 3b is at least 3 mm or more, for example, 2.0% to 3.5% of the tread width TW. The groove widths of the first peaks 3c and second peaks 3d may be configured to be slightly larger than the groove width W1. The depth of the circumferential grooves 3 is, for example, 5 to 15 mm. The tread width TW corresponds to the axial distance from the first tread edge T1 to the second tread edge T2 in the normal state of the tire.

[0020] In this specification, when a numerical range of various parameters is described, unless otherwise specified, the numerical range refers to the average value of the parameter. Therefore, the numerical range of the groove width of the first inclined portion 3a and the second inclined portion 3b described above refers to the average numerical range of the groove width measured at various positions on the first inclined portion 3a and the second inclined portion 3b. The same applies to other parameters described below.

[0021] The zigzag amplitude A1 of the circumferential groove 3 in the tire axial direction is, for example, 10% to 20% of the tread width TW. Note that the zigzag amplitude refers to the amplitude of the circumferential groove 3 in the tire axial direction about the groove center line.

[0022] The multiple circumferential grooves 3 include a first shoulder circumferential groove 5, a second shoulder circumferential groove 6, and at least one crown circumferential groove 7. The first shoulder circumferential groove 5 is adjacent to the first tread edge T1. The second shoulder circumferential groove 6 is adjacent to the second tread edge T2. The crown circumferential groove 7 is arranged between the first shoulder circumferential groove 5 and the second shoulder circumferential groove 6. In this embodiment, three crown circumferential grooves 7 are arranged between the first shoulder circumferential groove 5 and the second shoulder circumferential groove 6.

[0023] The three crown circumferential grooves 7 are arranged at equal intervals in the tire axial direction between the first shoulder circumferential groove 5 and the second shoulder circumferential groove 6. In this embodiment, one crown circumferential groove 7 is arranged so as to cross the tire equator C multiple times, and two crown circumferential grooves 7 are arranged so as to sandwich this crown circumferential groove 7. However, the present invention is not limited to this embodiment.

[0024] All of the plurality of circumferential grooves 3 are arranged in the same zigzag phase with respect to one another. This characteristic means that the following conditions (1) and (2) are satisfied. (1) The first peaks 3c of each circumferential groove 3 are arranged so as to be aligned in the tire axial direction, and the maximum distance in the tire circumferential direction between the first peaks 3c aligned in the tire axial direction is within a range of 10% or less of one pitch length P1 of the circumferential groove 3. (2) The second peaks 3d of each circumferential groove 3 are arranged so as to be aligned in the tire axial direction, and the maximum distance in the tire circumferential direction between the second peaks 3d aligned in the tire axial direction is within a range of 10% or less of one pitch length P1 of the circumferential groove 3.

[0025] The one pitch length P1 refers to the circumferential length of one first inclined portion 3a and one second inclined portion 3b (measured along the groove centerline). When the first peaks 3c have a circumferential length, the circumferential distance between the first peaks 3c is measured at the circumferential center of the first peaks 3c. In a preferred embodiment, the maximum circumferential distance specified by the above conditions (1) and (2) is substantially zero.

[0026] The land portion 4 includes a first shoulder land portion 8, a second shoulder land portion 9, a first crown land portion 11, and a second crown land portion 12. The first shoulder land portion 8 includes a first tread edge T1. The second shoulder land portion 9 includes a second tread edge T2. The first crown land portion 11 is adjacent to the first shoulder land portion 8. The second crown land portion 12 is adjacent to the first crown land portion 11.

[0027] Furthermore, the land portion 4 of this embodiment includes a third crown land portion 13 and a fourth crown land portion 14. The third crown land portion 13 is adjacent to the second crown land portion 12. The fourth crown land portion 14 is adjacent to the third crown land portion 13 and the second shoulder land portion 9. The configuration of the first crown land portion 11 can be applied to the third crown land portion 13. The configuration of the second crown land portion 12 can be applied to the fourth crown land portion 14. Therefore, a description of the third crown land portion 13 and the fourth crown land portion 14 will be omitted.

[0028] Fig. 2 shows an enlarged view of the first crown land portion 11 and the second crown land portion 12. As shown in Fig. 2, the first crown land portion 11 is divided into a plurality of first crown blocks 18 by a plurality of first inclined grooves 16 inclined in the first direction with respect to the tire axial direction. Also, the second crown land portion 12 is divided into a plurality of second crown blocks 19 by a plurality of second inclined grooves 17 inclined in the second direction with respect to the tire axial direction.

[0029] Fig. 3 shows an enlarged view of the first shoulder land portion 8 and the second shoulder land portion 9. Note that Fig. 3 omits the land portion between the first shoulder land portion 8 and the second shoulder land portion 9. As shown in Fig. 3, the first shoulder land portion 8 is divided into a plurality of first shoulder blocks 23 by a plurality of first shoulder lateral grooves 21. The plurality of first shoulder lateral grooves 21 communicate between the first tread edge T1 and the first shoulder circumferential groove 5 and extend along the tire axial direction.

[0030] The second shoulder land portion 9 is divided into a plurality of second shoulder blocks 24 by a plurality of second shoulder lateral grooves 22. The plurality of second shoulder lateral grooves 22 communicate between the second tread edge T2 and the second shoulder circumferential groove 6 and extend along the tire axial direction. By adopting the above-described configuration, the tire 1 of the present invention can exhibit excellent traction performance and braking performance while maintaining lateral grip. The reason for this is as follows.

[0031] As shown in Fig. 1, in the tire of the present invention, all of the multiple circumferential grooves 3 are arranged in a zigzag phase with respect to one another. Also, as shown in Fig. 2, the first crown land portion 11 is divided into multiple first crown blocks 18 by the above-mentioned first oblique grooves 16. The second crown land portion 12 is divided into multiple second crown blocks 19 by the above-mentioned second oblique grooves 17. In the tire 1 of the present invention, these circumferential grooves 3 and oblique grooves provide a large friction force in the tire axial direction, enabling the tire to maintain lateral grip.

[0032] 3, the tire 1 of the present invention includes the first shoulder lateral grooves 21 and the second shoulder lateral grooves 22 as described above, and these lateral grooves provide a large friction force in the tire circumferential direction, enabling the tire 1 to exhibit excellent traction and braking performance. Due to this mechanism, the tire 1 of the present invention can exhibit excellent traction and braking performance while maintaining lateral grip.

[0033] The following describes the configuration of this embodiment in more detail. Note that each configuration described below represents a specific aspect of this embodiment. Therefore, it goes without saying that the present invention can achieve the above-described effects even if it does not include the configurations described below. Furthermore, even if any one of the configurations described below is applied alone to the tire 1 of the present invention having the above-described characteristics, an improvement in performance corresponding to each configuration can be expected. Furthermore, when several of the configurations described below are applied in combination, an improvement in combined performance corresponding to those configurations can be expected.

[0034] As shown in Fig. 2, the axial width W2 of the tread surface of the first crown land portion 11 is, for example, 20% to 30% of the tread width TW (shown in Fig. 1), as is the case with the second crown land portion 12. This improves traction performance and cornering performance in a well-balanced manner.

[0035] Each of the multiple first inclined grooves 16 communicates with the second inclined portion 5b of the first shoulder circumferential groove 5 and the second inclined portion 7b of the adjacent crown circumferential groove 7. The angle of the first inclined grooves 16 with respect to the tire circumferential direction is 45 to 55 degrees, and in a preferred embodiment, the first inclined grooves 16 extend parallel to the first inclined portion 5a of the first shoulder circumferential groove 5. As a result, the first crown block 18 includes a main body portion 18a defined between the first inclined portion 5a of the first shoulder circumferential groove 5 and the first inclined portion 7a of the crown circumferential groove 7, and a first protruding portion 18b and a second protruding portion 18c connected to the main body portion 18a.

[0036] The first protrusion 18b is connected to one circumferential side of the main body 18a (the upper side in FIG. 2 ) and is separated between the second inclined portion 5b of the first shoulder circumferential groove 5, the second inclined portion 5b of the crown circumferential groove 7, and the first inclined groove 16. The second protrusion 18c is connected to the other circumferential side of the main body 18a (the lower side in FIG. 2 ) and is separated between the second inclined portion 5b of the first shoulder circumferential groove 5, the second inclined portion 7b of the crown circumferential groove 7, and the first inclined groove 16. As a result, the first crown block 18 has a tread surface that is curved in an S-shape in a tread plan view. Such a first crown block 18 exerts strong lateral grip and can provide a strong reaction force while deforming appropriately when stress is applied in the circumferential direction of the tire.

[0037] Each of the multiple second inclined grooves 17 communicates with the first inclined portions 7a of the two crown circumferential grooves 7. The angle of the second inclined grooves 17 with respect to the tire circumferential direction is 45 to 55 degrees, and in a preferred embodiment, the second inclined grooves 17 extend parallel to the second inclined portions 5b of the first shoulder circumferential groove 5. As a result, the second crown block 19 includes a main body portion 19a separated by the second inclined portions 7b of the two crown circumferential grooves 7, and a first protruding portion 19b and a second protruding portion 19c connected to the main body portion 19a.

[0038] The first protrusion 19b is connected to one circumferential side (upper side in FIG. 2 ) of the main body 19a and divides the first inclined portions 7a of the two crown circumferential grooves 7 and the second inclined groove 17. The second protrusion 19c is connected to the other circumferential side (lower side in FIG. 2 ) of the main body 19a and divides the first inclined portions 7a of the two crown circumferential grooves 7 and the second inclined groove 17. As a result, the second crown block 19 has an S-shaped tread surface that is curved in the opposite direction to the first crown block 18 in a tread plan view. This allows the first crown block 18 and the second crown block 19 to cooperate to provide frictional force in multiple directions. Note that the S-shaped tread surface curved in the opposite direction means that when the first crown block 18 and the second crown block 19 are aligned across an imaginary reference line, the tread surfaces of these blocks are substantially symmetrical with respect to the imaginary reference line.

[0039] The circumferential length L1 of the tread surface of the first crown block 18 or the tread surface of the second crown block 19 is 110% to 130% of the axial width W2 of the tread surface of the first crown land portion 11. This improves traction performance and cornering performance in a well-balanced manner.

[0040] As shown in Fig. 3, the maximum axial width W3 of the tread surface of the first shoulder land portion 8 is 20% to 30% of the tread width TW (shown in Fig. 1). The maximum axial width W4 of the tread surface of the second shoulder land portion 9 is 20% to 30% of the tread width TW (shown in Fig. 1). However, the present invention is not limited to this embodiment.

[0041] The angle θ1 of the first shoulder lateral grooves 21 relative to the tire axial direction is, for example, 10° or less, and preferably 5° or less. More preferably, the angle θ2 of the first shoulder lateral grooves 21 of this embodiment is 0°. Such first shoulder lateral grooves 21 reliably improve traction performance and braking performance.

[0042] Similarly, the angle θ2 of the second shoulder lateral grooves 22 relative to the tire axial direction is, for example, 10° or less, and preferably 5° or less. More preferably, the angle θ2 of the second shoulder lateral grooves 22 of this embodiment is 0°.

[0043] The depth of the first shoulder lateral grooves 21 is, for example, 1 to 9 mm. Similarly, the depth of the second shoulder lateral grooves 22 is, for example, 1 to 9 mm. In another embodiment, the depth of the first shoulder lateral grooves 21 may gradually decrease toward the first tread edge T1 (not shown). Also, the depth of the second shoulder lateral grooves 22 may gradually decrease toward the second tread edge T2 (not shown).

[0044] The multiple first shoulder lateral grooves 21 include those that connect to the first peaks 5c and those that connect to the second peaks 5d of the first shoulder circumferential grooves 5. The average depth of the first shoulder lateral grooves 21 that connect to the first peaks 5c is 0.5 to 2.0 mm smaller than the average depth of the first shoulder lateral grooves 21 that connect to the second peaks 5d. This results in differences in the tendency of blocks to collapse between these grooves. Therefore, when traveling on rough terrain, dirt and mud that has entered the lateral grooves is easily expelled, allowing the tire to maintain excellent off-road performance.

[0045] The second shoulder lateral grooves 22 include deep second shoulder lateral grooves 22a and shallow second shoulder lateral grooves 22b, each of which is deeper than the deep second shoulder lateral grooves 22a and alternates in the tire circumferential direction. The average depth of the shallow second shoulder lateral grooves 22b is, for example, 40% to 60% of the average depth of the deep second shoulder lateral grooves 22a. This maintains the rigidity of the second shoulder land portion 9 and improves vehicle controllability during cornering.

[0046] The shallow second shoulder lateral groove 22b communicates with the first crest 6c of the second shoulder circumferential groove 6. The deep second shoulder lateral groove 22a communicates with the second crest 6d of the second shoulder circumferential groove 6. As a result, the axial length of the shallow second shoulder lateral groove 22b is greater than the axial length of the deep second shoulder lateral groove 22a. This makes it possible to more reliably maintain the rigidity of the second shoulder land portion 9.

[0047] The first shoulder blocks 23 have, for example, trapezoidal tread surfaces 23s. As a result, the axial length of the tread surfaces of the first shoulder blocks 23 continuously decreases toward one side or the other in the tire circumferential direction. In a preferred embodiment, first shoulder blocks 23 whose tread length continuously decreases toward one side in the tire circumferential direction and first shoulder blocks 23 whose tread length continuously decreases toward the other side in the tire circumferential direction are arranged alternately in the tire circumferential direction. Such first shoulder blocks 23 help to improve traction performance and braking performance in a balanced manner.

[0048] The circumferential length L2 of the tread surface 23s of each first shoulder block 23 is 30% to 45% of the circumferential length L1 (shown in FIG. 2) of the tread surface 18s of each first crown block 18. This allows the first shoulder blocks 23 to deform appropriately in the circumferential direction of the tire, improving traction and braking performance on soft, uneven terrain. The total area of ​​the tread surfaces 23s of the multiple first shoulder blocks 23 is 80% to 120% of the total area of ​​the tread surfaces 18s (shown in FIG. 2) of the multiple first crown blocks 18. This reduces uneven wear of these blocks.

[0049] The second shoulder block 24 can be applied with the features of the first shoulder block 23 described above.

[0050] The total area of ​​the tread surfaces 24s of the plurality of second shoulder blocks 24 is 70% to 120% of the total area of ​​the tread surfaces 23s of the plurality of first shoulder blocks 23. This optimizes the amount of deformation of these blocks, improving vehicle controllability.

[0051] The first shoulder block 23 and the second shoulder block 24 each have greater axial rigidity than the first crown block 18 (shown in FIG. 1), thereby improving lateral grip and vehicle controllability.

[0052] In this embodiment, the shallow second shoulder lateral grooves 22b are arranged so that the circumferential rigidity of the second shoulder land portion 9 is greater than the rigidity of the first shoulder land portion 8. When the tire 1 of this embodiment is mounted on a vehicle, the second shoulder land portion 9 is located on the outer side of the vehicle, which further improves vehicle controllability.

[0053] Figure 4 shows a developed view of a tread portion 2 according to another embodiment of the present invention. As shown in Figure 4, in this embodiment, the depth of the first shoulder lateral grooves 21 is also adjusted. That is, the multiple first shoulder lateral grooves 21 include multiple deep first shoulder lateral grooves 21a and shallow first shoulder lateral grooves 21b, each having a depth smaller than that of the deep first shoulder lateral grooves 21a, arranged alternately in the tire circumferential direction. The average depth of the shallow first shoulder lateral grooves 21b is, for example, 40% to 60% of the average depth of the deep first shoulder lateral grooves 21a.

[0054] In this embodiment, the shallow first shoulder lateral groove 21b communicates with the first crest 5c of the first shoulder circumferential groove 5, and the deep first shoulder lateral groove 21a communicates with the second crest 5d of the first shoulder circumferential groove 5. That is, the axial length of the shallow first shoulder lateral groove 21b is shorter than the axial length of the shallow second shoulder lateral groove 22b. This optimizes the rigidity distribution between the first shoulder land portion 8 and the second shoulder land portion 9, resulting in a balanced improvement in traction performance and vehicle controllability.

[0055] Although a tire according to one embodiment of the present invention has been described in detail above, the present invention is not limited to the specific embodiment described above, and can be modified and practiced in various aspects. [Example]

[0056] Pneumatic tires of size 205 / 65R15 having the basic pattern of Fig. 1 or Fig. 4 were produced as prototypes. As comparative examples, tires without the first shoulder lateral grooves and second shoulder lateral grooves of the present invention arranged in the tread portion, as shown in Fig. 5, were produced as prototypes. The comparative tire had substantially the same configuration as the tire of the example, except for the pattern configuration. Each test tire was tested for lateral grip, traction performance, braking performance, and vehicle controllability. The common specifications and test methods for each test tire are as follows. Rim: 15 x 7J Tire pressure: All wheels: 200kPa Test vehicle: 2000cc, four-wheel drive Tire mounting position: All wheels

[0057] <Lateral grip, traction, braking performance and vehicle control> The test vehicle was driven on rough terrain and various driving performances were evaluated by the driver. The results were given as a rating indicating the driving performance, with a higher rating indicating better driving performance. The test results are shown in Table 1.

[0058] [Table 1]

[0059] As shown in Table 1, it was confirmed that the tires of Examples 1 and 2 exhibited excellent traction and braking performance while maintaining at least lateral grip. It was also confirmed that the tire of Example 2, by optimizing the depth of the shoulder lateral grooves, improved not only the traction and braking performance but also the lateral grip and vehicle controllability.

[0060] [Note] The present invention includes the following aspects.

[0061] [Invention 1] A tire having a tread portion, the tread portion includes a first tread edge, a second tread edge, a plurality of circumferential grooves extending continuously in a zigzag pattern in the tire circumferential direction between the first tread edge and the second tread edge, and a plurality of land portions separated by the circumferential grooves, the plurality of circumferential grooves include a first shoulder circumferential groove adjacent to the first tread edge, a second shoulder circumferential groove adjacent to the second tread edge, and at least one crown circumferential groove disposed between the first shoulder circumferential groove and the second shoulder circumferential groove, All of the plurality of circumferential grooves are arranged in a zigzag phase with one another, the land portion includes a first shoulder land portion including the first tread edge, a second shoulder land portion including the second tread edge, a first crown land portion adjacent to the first shoulder land portion, and a second crown land portion adjacent to the first crown land portion, The first crown land portion is divided into a plurality of first crown blocks by a plurality of first inclined grooves inclined in a first direction with respect to the tire axial direction, the second crown land portion is divided into a plurality of second crown blocks by a plurality of second inclined grooves inclined in a second direction, which is a direction opposite to the first direction with respect to the tire axial direction, The first shoulder land portion is divided into a plurality of first shoulder blocks by a plurality of first shoulder lateral grooves, the plurality of first shoulder lateral grooves communicate with the first tread edge and the first shoulder circumferential groove and extend along the tire axial direction, The second shoulder land portion is divided into a plurality of second shoulder blocks by a plurality of second shoulder lateral grooves, The plurality of second shoulder lateral grooves communicate with the second tread edge and the second shoulder circumferential groove and extend along the tire axial direction. tire. [Invention 2] The tire according to Invention 1, wherein the angle of the first shoulder lateral groove with respect to the tire axial direction is 10° or less. [Invention 3] 3. The tire according to claim 1, wherein the angle of the second shoulder lateral groove with respect to the tire axial direction is 10° or less. [Invention 4] 4. The tire according to any one of claims 1 to 3, wherein the first shoulder lateral groove has a depth of 1 to 9 mm. [Invention 5] 5. The tire according to any one of claims 1 to 4, wherein the second shoulder lateral groove has a depth of 1 to 9 mm. [Invention 6] The tire according to any one of claims 1 to 5, wherein the total area of ​​the tread surfaces of the first shoulder blocks is 80% to 120% of the total area of ​​the tread surfaces of the first crown blocks. [Invention 7] The tire according to any one of claims 1 to 6, wherein the total area of ​​the tread surfaces of the second shoulder blocks is 70% to 120% of the total area of ​​the tread surfaces of the first shoulder blocks. [Invention 8] The tire according to any one of claims 1 to 7, wherein the plurality of first shoulder lateral grooves include a plurality of deep first shoulder lateral grooves and shallow first shoulder lateral grooves having a depth smaller than that of the deep first shoulder lateral grooves, alternately arranged in the tire circumferential direction. [Invention 9] The tire according to invention 8, wherein the axial length of the shallow first shoulder lateral grooves is smaller than the axial length of the deep first shoulder lateral grooves. [Invention 10] The tire according to any one of claims 1 to 9, wherein the plurality of second shoulder lateral grooves include a plurality of deep second shoulder lateral grooves and shallow second shoulder lateral grooves having a depth smaller than that of the deep second shoulder lateral grooves, alternately arranged in the tire circumferential direction. [Invention 11] The tire according to claim 10, wherein the axial length of the shallow second shoulder lateral grooves is greater than the axial length of the deep second shoulder lateral grooves. [Explanation of symbols]

[0062] 2 Tread section 3 Circumferential groove 4 Land 5 First shoulder circumferential groove 6 Second shoulder circumferential groove 7 Crown circumferential groove 8 First Shoulder Land Section 9 Second Shoulder Land Section 11 Crown No. 1 Land Section 12 Crown No. 2 Land Section 16 1st inclined groove 17 2nd inclined groove 18 1st Crown Block 19 2nd Crown Block 21 First shoulder groove 23 First Shoulder Block T1 First tread edge T2 Second tread edge

Claims

1. A tire having a tread portion, the tread portion includes a first tread edge, a second tread edge, a plurality of circumferential grooves extending continuously in a zigzag pattern in the tire circumferential direction between the first tread edge and the second tread edge, and a plurality of land portions separated by the circumferential grooves, the plurality of circumferential grooves include a first shoulder circumferential groove adjacent to the first tread edge, a second shoulder circumferential groove adjacent to the second tread edge, and at least one crown circumferential groove disposed between the first shoulder circumferential groove and the second shoulder circumferential groove, All of the plurality of circumferential grooves are arranged in a zigzag phase with one another, the land portion includes a first shoulder land portion including the first tread edge, a second shoulder land portion including the second tread edge, a first crown land portion adjacent to the first shoulder land portion, and a second crown land portion adjacent to the first crown land portion, the first crown land portion is divided into a plurality of first crown blocks by a plurality of first inclined grooves inclined in a first direction with respect to the tire axial direction, the second crown land portion is divided into a plurality of second crown blocks by a plurality of second inclined grooves inclined in a second direction, which is a direction opposite to the first direction with respect to the tire axial direction, The first shoulder land portion is divided into a plurality of first shoulder blocks by a plurality of first shoulder lateral grooves, the plurality of first shoulder lateral grooves communicate with the first tread edge and the first shoulder circumferential groove and extend along the tire axial direction, the second shoulder land portion is divided into a plurality of second shoulder blocks by a plurality of second shoulder lateral grooves, the plurality of second shoulder lateral grooves communicate with the second tread edge and the second shoulder circumferential groove and extend along the tire axial direction; tire.

2. The tire according to claim 1 , wherein the angle of the first shoulder lateral groove with respect to the tire axial direction is 10° or less.

3. The tire according to claim 2 , wherein the angle of the second shoulder lateral groove with respect to the tire axial direction is 10° or less.

4. 4. The tire according to claim 1, wherein the first shoulder lateral groove has a depth of 1 to 9 mm.

5. 4. The tire according to claim 1, wherein the second shoulder lateral groove has a depth of 1 to 9 mm.

6. 4. The tire according to claim 1, wherein a total area of ​​the tread surfaces of the plurality of first shoulder blocks is 80% to 120% of a total area of ​​the tread surfaces of the plurality of first crown blocks.

7. 4. The tire according to claim 1, wherein a total area of ​​the tread surfaces of the second shoulder blocks is 70% to 120% of a total area of ​​the tread surfaces of the first shoulder blocks.

8. 4. The tire according to claim 1, wherein the plurality of first shoulder lateral grooves include a plurality of deep first shoulder lateral grooves and shallow first shoulder lateral grooves having a depth smaller than that of the deep first shoulder lateral grooves, alternately arranged in the tire circumferential direction.

9. The tire according to claim 8 , wherein the axial length of the shallow first shoulder lateral groove is smaller than the axial length of the deep first shoulder lateral groove.

10. 4. The tire according to claim 1, wherein the plurality of second shoulder lateral grooves include a plurality of deep second shoulder lateral grooves and shallow second shoulder lateral grooves having a depth smaller than that of the deep second shoulder lateral grooves, alternately arranged in the tire circumferential direction.

11. The tire according to claim 10, wherein the axial length of the shallow second shoulder lateral groove is greater than the axial length of the deep second shoulder lateral groove.

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